Resilient Pick Shank

ABSTRACT

In one aspect of the invention, a pick assembly comprises a pick shank press fitted within a bore of a pick holder. The pick comprises a pick head opposite the shank. The shank also comprises at least one longitudinal slot extending towards the pick head along the shank from a distal end of the shank. The slot allows the shank to resiliently collapse upon insertion into the bore while still allowing the shank to maintain a press fit while within the bore.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation in part of U.S. patent application Ser. No. 11/962,497. This application is also a continuation in part of U.S. patent application Ser. No. 12/177,556 which is a continuation-in-part of U.S. patent application Ser. No. 12/135,595 which is a continuation-in-part of U.S. patent Ser. No. 12/112,743 which is a continuation-in-part of U.S. patent application Ser. No. 12/051,738 which is a continuation-in-part of U.S. patent application Ser. No. 12/051,689 which is a continuation of U.S. patent application Ser. No. 12/051,586 which is a continuation-in-part of U.S. patent application Ser. No. 12/021,051 which is a continuation-in-part of U.S. patent application Ser. No. 12/021,019 which was a continuation-in-part of U.S. patent application Ser. No. 11/971,965 which is a continuation of U.S. patent application Ser. No. 11/947,644, which was a continuation-in-part of U.S. patent application Ser. No. 11/844,586 which is a continuation-in-part of U.S. patent application Ser. No. 11/829,761, which is a continuation-in-part of U.S. patent application Ser. No. 11/773,271, which is a continuation-in-part of U.S. patent application Ser. No. 11/766,903, which is a continuation of U.S. patent application Ser. No. 11/766,865, which is a continuation-in-part of U.S. patent application Ser. No. 11/742,304, which is a continuation of U.S. patent application Ser. No. 11/742,261, which is a continuation-in-part of U.S. patent application Ser. No. 11/464,008, which is a continuation-in-part of U.S. patent application Ser. No. 11/463,998, which is a continuation-in-part of U.S. patent application Ser. No. 11/463,990, which is a continuation-in-part of U.S. patent application Ser. No. 11/463,975, which is a continuation-in-part of U.S. patent application Ser. No. 11/463,962, which is a continuation-in-part of U.S. patent application Ser. No. 11/463,953. The present application is also a continuation-in-part of U.S. patent application Ser. No. 11/695,672, which is a continuation-in-part of U.S. patent application Ser. No. 11/686,831. All of these applications are herein incorporated by reference for all that they contain.

BACKGROUND OF THE INVENTION

Formation degradation, such as asphalt milling, mining, or excavating, may result in wear on attack tools. Consequently, many efforts have been made to efficiently remove and replace these tools.

U.S. Pat. No. 6,585,326 to Sollami, which is herein incorporated by reference for all that it contains, discloses a bit holder with its mating bit block utilizing a slight taper in the bit block bore, and a tapered shank on the bit holder that includes a second larger diameter tapered distal segment that combines with an axially oriented slot through the side wall of the bit holder shank to allow a substantially larger interference fit between the distal tapered shank segment and the bit block bore than previously known. When inserting the bit holder in the bit block bore, the distal first tapered segment resiliently collapses to allow insertion of that segment into the bit block bore. A second shank tapered portion axially inwardly of the first distal tapered portion. The dual tapered shank allows the insertion of the bit holder in the bit block with an interference fit that provides a secure mounting of the bit holder in the bit block.

U.S. Pat. No. 3,751,115 to Proctor, which is herein incorporated by reference for all that it contains, discloses a combination of a shanked tool and a holder therefore the holder being formed with a socket for receiving the tool shank and with a resilient latch biased in a direction transverse to the operating direction for engaging in a recess in the side of the tool shank.

U.S. Pat. No. 3,468,553 to Ashby et al., which is herein incorporated by reference for all that it contains, discloses a tool retaining device having a metal locking pin bonded in a groove of a resilient backing member. One end of the backing member is formed with an integral end sealing cap and the other end has a projecting spigot onto which a further end sealing cap is fitted when the device is fitted in a tool holder. In the fitted position, the two sealing caps respectively seal the ends of the device and thereby prevent the ingress of foreign matter.

In accordance to the U.S. Pat. No. 3,865,437 to Crosby, which is herein incorporated by reference for all that it contains, a mining tool of the type in which a pick style bit is rotatably mounted in a bore in a support member and is retained therein by retaining means integrally formed on the bit. The retaining means advantageously takes the form of at least one radial projection on the rear end of the bit shank with the bit shank being slotted to impart radial resilience thereto so the bit can be assembled with the support member and readily disassembled therefrom while being retained therein during work operations. The support member may comprise a support block adapted for being fixed to a driver with a sleeve rotatable in a bore in the block and in turn, rotatably receiving the bit. The sleeve may be slotted axially from the rear end so as to have lateral resilience and be formed with one or more radial projections or protrusions at the rear end so that the sleeve, also, is releasably retained in the block by retaining means integral therewith.

Examples of degradation tools from the prior art are disclosed in U.S. Pat. No. 2,989,295 to Prox Jr., U.S. Pat. No. 6,397,652 B1 to Sollami, U.S. Pat. No. 6,685,273 B1 to Sollami, which are all herein incorporated by reference for all they contain.

BRIEF SUMMARY OF THE INVENTION

In one aspect of the invention, a pick assembly comprises a pick shank press fitted within a bore of a pick holder. The pick comprises a pick head opposite the shank. The shank also comprises at least one longitudinal slot extending towards the pick head along the shank from a distal end of the shank. The slot allows the shank to resiliently collapse upon insertion into the bore while still allowing the shank to maintain a press fit while within the bore.

The shank may comprise a tapered portion proximate the pick head. The shank may comprise a reduced outer diameter portion disposed intermediate the tapered portion and the distal end. The slot may extend to a second end of the tapered portion from the distal end of the shank. The tapered portion may comprise a first end attached to the pick head and the second end connected to the reduced diameter portion of the shank. At least one slot may comprise a tapered geometry. The shank may comprise a bore extending form the distal end to an interface of a bolster and the shank. The bore proximate the interface may comprise a smaller inner diameter than the region of the bore proximate the slot.

A first wall thickness of the bore proximate the tapered portion of the shank may be at least twice as thick as a second wall thickness of the portion of the shank proximate the slot. The bore may comprise at least one recess formed on an inner diameter of the shank. The pick may comprise a plurality of slots, at least one of the slots comprising a different width. At least one slot may be forging into the shank. At least one slot may be arranged spirally with respect to the central axis of the shank. The slot may collapse upon insertion into a bore of the holder by one to five percent of the diameter of the shank. A ratio of the width of the slots and the number of slots in the shank may range from 0.01 to 0.07.

In another aspect of the present invention, at least some portion of the shank may comprise threads. At least some portion of the bore of the pick holder may comprise threads spaced within the bore to threadably connect with the threads of the shank. The slot may collapse upon insertion into a bore of a holder by one to five percent of the diameter of the shank.

In yet another aspect of the invention, a carbide bolster supports a diamond enhanced tip. The tip is bonded to the bolster at a forward end of the bolster and a centralized cavity is formed on a rearward end of the bolster. The rearward end of the bolster is also bonded to a steel shank at a non-planar interface. At least one void is in the interface.

The non-planar interface may be tapered and/or comprise a step. In embodiments with steps, the void may be formed proximate the step.

The void may be located at the center of the interface and a portion of the void may be formed in both the steel shank and the carbide bolster. The portion of the void formed in the steel shank may run through the shank along the shank's central axis to an opening in a rearward end of the shank.

The void may be an annular groove formed in the forward end of the steel shank. The void may also be formed in the rearward end of the carbide bolster. In some embodiments, a first void may be formed at the center of the interface and at least a second void, in the form of an annular groove, may be formed distally to the first void.

The interface may comprise at least one protrusion that controls the thickness of a braze material disposed therein. A bonding material disposed at the interface may be thicker towards a periphery of the interface. The bonding material may comprise 30 to 60 percent palladium.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective diagram of an embodiment of a pick assembly.

FIG. 2 is a cross-sectional diagram of an embodiment of a pick assembly.

FIG. 3 is a perspective diagram of an embodiment of a holder assembly.

FIG. 4 is a cross-sectional diagram of another embodiment of a holder assembly.

FIG. 5 is a perspective diagram on another embodiment of a holder assembly.

FIG. 6 is a cross-sectional diagram of an embodiment of a pick assembly.

FIG. 7 is a cross-sectional diagram of an embodiment of a pick assembly.

FIG. 7 a is a cross-sectional diagram of an embodiment of a pick assembly.

FIG. 7 b is a cross-sectional diagram of an embodiment of a pick assembly.

FIG. 7 c is a cross-sectional diagram of an embodiment of a pick assembly.

FIG. 7 d is a cross-sectional diagram of an embodiment of a pick assembly.

FIG. 8 is a perspective diagram of another embodiment of a pick assembly.

FIG. 9 is a perspective diagram of another embodiment of a pick assembly.

FIG. 10 is a perspective diagram of another embodiment of a pick assembly.

FIG. 11 is a perspective diagram of another embodiment of a pick assembly.

FIG. 12 is a perspective diagram of another embodiment of a pick assembly.

FIG. 13 a is an orthogonal diagram of an embodiment of a pick shank.

FIG. 13 b is an orthogonal diagram of another embodiment of a pick shank.

FIG. 13 c is an orthogonal diagram of another embodiment of a pick shank.

FIG. 13 d is an orthogonal diagram of another embodiment of a pick shank.

FIG. 13 e is an orthogonal diagram of another embodiment of a pick shank.

FIG. 14 is a cross-sectional diagram of an embodiment of an asphalt milling machine.

FIG. 15 is a cross-sectional diagram of an embodiment of a roller cone bit.

FIG. 16 is a perspective diagram of an embodiment of a mining pick.

FIG. 17 is an orthogonal diagram of an embodiment of a drill bit.

FIG. 18 is a perspective diagram of another embodiment of a trenching machine.

FIG. 19 is a perspective diagram of an embodiment of a chisel.

FIG. 20 is a perspective diagram of another embodiment of a moil.

FIG. 21 is an orthogonal diagram of an embodiment of a coal excavator.

DETAILED DESCRIPTION OF THE INVENTION AND THE PREFERRED EMBODIMENT

Referring to FIG. 1, a pick assembly 101 comprises a shank 102 and a pick head 104 opposite the shank 102. The shank 102 may comprise a tapered portion 105 proximate the pick head 104. The shank 102 may be tapered at a four to seven degree from the shank's longitudinal axis. The tapered portion 105 may comprise a first end 108 attached to the pick head 104 and the second end 110 connected to the shank's reduced diameter portion 111 that is disposed intermediate the shank's tapered portion 105 and the shank's distal end 120. The shank 102 may comprise at least one longitudinal slot 112 extending from the distal end 120 towards the pick head 104. The slots 112 may extend to a second end 110 of the tapered portion 105 from the distal end 120. The slots 112 may be made by using a band saw, CNC machine or combinations thereof. At least one slot 112 may be forging into the shank 102.

The pick head 104 may comprise an impact tip 114 attached to a bolster 201. The impact tip 114 may comprise a super hard material bonded to a carbide substrate at a non-planar interface. The super hard material may comprise diamond, polycrystalline diamond with a binder concentration of 1 to 40 weight percent, cubic boron nitride, silicon bonded diamond, layered diamond, infiltrated diamond, thermally stable diamond, natural diamond, vapor deposited diamond, physically deposited diamond, monolithic diamond, polished diamond, course diamond, fine diamond, nonmetal catalyzed diamond, cemented metal carbide, chromium, titanium, aluminum, tungsten, or combinations thereof.

FIG. 2 discloses the bore 204 extending from the distal end 120 to an interface 205 between the bolster 201 and the shank 102. The bore 204 proximate the interface 205 may comprise a smaller inner diameter than the bore 204 that is proximate the slot 112. The bore's smaller diameter may allow a thicker wall at the tapered portion 105 than proximate the distal end 120. The thicker wall may help stabilize the shank and reduce bending moments while the pick assembly is in use. Furthermore, the tapered portion 105 may comprise more contact surface area between the tapered outer surface of the shank 102 and an inner surface of a pick holder 301. The tapered portion 105 may act as a supporting seat. The thinner wall proximate the distal end 120 may allow the shank 102 to resiliently collapse upon insertion into the bore while still allowing the shank 102 to maintain a press fit while within the bore.

The shank 102 may comprise a cylindrical geometry. The pick assembly 101 may be manually rotated by removing the pick shank from the holder and reinserting it in the desired orientation. In some embodiments, the pick assembly 101 is rotationally fixed within the holder's bore.

The present invention may allow quick replacement the pick assembly 101. The shank 102 may be press fitted inside the pick holder 301 with an air hammer or similar tools. The distal end may reside within the holder's bore after insertion and during operation. The distal end may have enough lateral spring force to overcome the centrifugal forces of the drum's rotation without requiring any interlocking features.

FIG. 3 discloses a pick assembly 101 press fitted within an insertable pick holder 301. FIGS. 4 and 5 are a cross-sectional and a perspective diagram, respectively, of another embodiment of a holder assembly 404.

FIG. 6 discloses the shank 102 with a bore 204 extending from the distal end 120 to the non-planar interface 205. Heated gases may be emitted while brazing the bolster 201 to the shank 102, which may interfere with bonding. These gases may escape through the bore 204. In some embodiments, the bore 204 may extend from the distal end 120 to the second end 108 of the tapered portion 105.

FIG. 7 discloses a reduced outer diameter portion 702 disposed intermediate the tapered portion 105 and the distal end 120. The reduced diameter portion 702 may allow more resilience in the portion of the shank portion with slots 112.

FIGS. 7 a-7 d discloses the non-planar interface 205 with void 650 or interruption formed therein. The void 650 or interruption may provide stress relief after the bonding process. Carbide and steel thermally expand and shrink at different rates during bonding process resulting in residual stress at the interface 205. The voids reduce stress. In some embodiments, the voids will also provide space for gases let off during the bonding process as well as extra bonding material.

The void may be formed in the forward end 651 of the steel shank 102 or the rearward end 652 of the carbide bolster 201. The void may be formed along a tapered portion of the interface as shown in FIGS. 6 a-c. In some embodiments, the void is formed proximate a step 653 of the interface as shown in FIG. 6 d.

The void may be formed at the interface's center. A portion of the void may be the bore 204 formed in the shank that runs to an opening 654 in the distal end 655 (see FIG. 7) of the shank. In some embodiments, the void 650 is in the form of an annular groove. In some embodiments, the both a first void 656, the void at the center, and a second void 657, an annular groove, may be used in conjunction.

A protrusion 658 may be formed in either the carbide or the steel to provide a space between them. This space may determine the bonding material's thickness along the interface. Preferably, the bonding material is thicker towards the interface's periphery to accommodate stress propagating down the pick's side during impacts. Also, the bonding material may comprises 30 to 60 percent palladium.

FIG. 8 discloses a slot 800 extending from the shank's distal end 120 to the second end 108 of the tapered portion 105. The present embodiment lacks a reduced diameter portion 702 intermediate the tapered portion 105 and the distal end 120.

FIG. 9 discloses a plurality of slots 112. Some slots 112 may extend to the distal end 120 while some slots 112 extend only proximate the distal end 120. The width of each slot 112 may decrease as the number of slots 112 increases. In some embodiments, the slots comprise different widths.

FIG. 10 discloses threads 1010 on the distal end. The shank 102 may be inserted into the holder's bore by turning the pick assembly 101 with a wrench or similar tool. The shank 102 may resiliently collapse as the parts are threaded together. The holder's bore may comprise internal to connect with the shank's threads 1010.

FIG. 11 discloses tapered slots 1110. The tapering may increase outwardly as the taper extends towards the distal end 120. Such tapering may allow more flexibility to the portion of the shank 102 proximate the distal end 120.

FIG. 12 discloses slots 1200 arranged spirally with respect to the shank's center. The present embodiment may allow more flexibility to the shank portion proximate the distal end 120. FIGS. 13 a-e disclose different cross sections of the shank portion proximate the distal end 120. The bore 204 may comprise at least one recess formed in the shank's inner surfaces and/or outer surfaces 1310, 1320.

The pick assembly 101 may be used in many different applications. The pick assembly 101 may be a pick in an asphalt milling machine 1400, as in the embodiment of FIG. 14.

The pick assembly 101 may be an insert in a drill bit, as in the embodiments of FIGS. 15-17. Further, the pointed geometry may be useful in roller cone bits 1500, where the inserts typically fail the formation through compression. The pointed geometries may be angled to enlarge the Huge well bore. FIG. 16 discloses a mining bit. FIG. 17 discloses a drill bit typically used in horizontal drilling.

The tool may be used in a trenching machine 1800, as in the embodiment of FIG. 18. The tools may be placed on a chain that rotates around an boom 1850.

Crushing or degradation machines may also incorporate the present invention. The milling machines may be used for size reduction in materials such as rocks, grain, trash, natural resources, chalk, wood, tires, metal, cars, tables, couches, coal, minerals, chemicals, or other natural resources.

Chisels 1900 may also incorporate the present invention. The invention may be placed on the impacting end 1950 of the chisel 1900 or moil 2000.

FIG. 21 discloses a mining machine 2100. The pick assemblies 101 may be connected to a rotating drum 2110 while degrading mineral or coal formations 2120. The rotating drum 2110 is connected to an arm 2150 that moves the drum 2110 vertically in order to engage the formation 2120. The arm 2150 may move by a hydraulic arm 2180, which may also pivot about an axis. The mining machine 2100 may move about by tracks, wheels, or a combination thereof. The mining machine 2100 may also move about in a subterranean formation.

Whereas the present invention has been described in particular relation to the drawings attached hereto, it should be understood that other and further modifications apart from those shown or suggested herein, may be made within the scope and spirit of the present invention. 

1. A pick assembly, comprising: a pick shank press fit within a bore of a pick holder; the pick comprising a pick head opposite the shank; the shank also comprising at least one longitudinal slot extending towards the pick head along the shank from a distal end of the shank; wherein the slot allows the shank to resiliently collapse upon insertion into the bore while still allowing the shank to maintain a press fit while within the bore.
 2. The pick of claim 1, wherein the shank comprises a tapered portion proximate the pick head.
 3. The pick of claim 2 wherein the shank comprises a reduced outer diameter portion disposed intermediate the tapered portion and the distal end.
 4. The pick of claim 2, wherein the slot extends to a second end of the tapered portion from the distal end of the shank.
 5. The pick of claim 2, wherein the tapered portion comprises a first end attached to the pick head and the second end connected to the reduced diameter portion of the shank.
 6. The pick of claim 1, wherein a surface area of contact between the tapered portion and an inner surface of the pick holder is greater than a surface area of contact between a shank portion proximate the distal end and the inner surface of the pick holder.
 7. The pick of claim 1, wherein at least one slot comprises a tapered geometry.
 8. The pick of claim 1, wherein the shank comprises a bore extending from the distal end to an interface of a bolster and the shank.
 9. The pick of claim 9, wherein the bore proximate the interface comprises a smaller inner diameter than the region of the bore proximate the slot.
 10. The pick of claim 10, wherein a first wall thickness of the bore proximate the tapered portion of the shank is at least twice as thick as a second wall thickness of the portion of the shank proximate the slot.
 11. The pick of claim 9, wherein the bore comprises at least one recess formed on an inner diameter of the shank.
 12. The pick of claim 1, wherein the pick comprises a plurality of slots, at least one of the slots comprising a different width.
 13. The pick of claim 1, wherein the at least one slot is forging into the shank.
 14. The pick of claim 1, wherein at least one slot is arranged spirally with respect to the central axis of the shank.
 15. The pick of claim 1, wherein at least some portion of the shank comprises threads.
 16. The pick of claim 16, wherein at least some portion of the bore of the pick holder comprises threads spaced within the bore to threadably connect with the threads of the shank.
 17. The pick of claim 1, wherein the slot collapses upon insertion into a bore of a holder by one to five percent of the diameter of the shank.
 19. The pick of claim 1, wherein the pick head comprises an impact tip comprising a super hard material. 